git.oblomov.eu Git - git/blob - fetch-pack.c

   1 #include "cache.h"
   2 #include "repository.h"
   3 #include "config.h"
   4 #include "lockfile.h"
   5 #include "refs.h"
   6 #include "pkt-line.h"
   7 #include "commit.h"
   8 #include "tag.h"
   9 #include "exec-cmd.h"
  10 #include "pack.h"
  11 #include "sideband.h"
  12 #include "fetch-pack.h"
  13 #include "remote.h"
  14 #include "run-command.h"
  15 #include "connect.h"
  16 #include "transport.h"
  17 #include "version.h"
  18 #include "sha1-array.h"
  19 #include "oidset.h"
  20 #include "packfile.h"
  21 #include "fetch-negotiator.h"
  22
  23 static int transfer_unpack_limit = -1;
  24 static int fetch_unpack_limit = -1;
  25 static int unpack_limit = 100;
  26 static int prefer_ofs_delta = 1;
  27 static int no_done;
  28 static int deepen_since_ok;
  29 static int deepen_not_ok;
  30 static int fetch_fsck_objects = -1;
  31 static int transfer_fsck_objects = -1;
  32 static int agent_supported;
  33 static int server_supports_filtering;
  34 static struct lock_file shallow_lock;
  35 static const char *alternate_shallow_file;
  36
  37 /* Remember to update object flag allocation in object.h */
  38 #define COMPLETE        (1U << 0)
  39 #define ALTERNATE       (1U << 1)
  40
  41 /*
  42  * After sending this many "have"s if we do not get any new ACK , we
  43  * give up traversing our history.
  44  */
  45 #define MAX_IN_VAIN 256
  46
  47 static int multi_ack, use_sideband;
  48 /* Allow specifying sha1 if it is a ref tip. */
  49 #define ALLOW_TIP_SHA1  01
  50 /* Allow request of a sha1 if it is reachable from a ref (possibly hidden ref). */
  51 #define ALLOW_REACHABLE_SHA1    02
  52 static unsigned int allow_unadvertised_object_request;
  53
  54 __attribute__((format (printf, 2, 3)))
  55 static inline void print_verbose(const struct fetch_pack_args *args,
  56                                  const char *fmt, ...)
  57 {
  58         va_list params;
  59
  60         if (!args->verbose)
  61                 return;
  62
  63         va_start(params, fmt);
  64         vfprintf(stderr, fmt, params);
  65         va_end(params);
  66         fputc('\n', stderr);
  67 }
  68
  69 struct alternate_object_cache {
  70         struct object **items;
  71         size_t nr, alloc;
  72 };
  73
  74 static void cache_one_alternate(const char *refname,
  75                                 const struct object_id *oid,
  76                                 void *vcache)
  77 {
  78         struct alternate_object_cache *cache = vcache;
  79         struct object *obj = parse_object(oid);
  80
  81         if (!obj || (obj->flags & ALTERNATE))
  82                 return;
  83
  84         obj->flags |= ALTERNATE;
  85         ALLOC_GROW(cache->items, cache->nr + 1, cache->alloc);
  86         cache->items[cache->nr++] = obj;
  87 }
  88
  89 static void for_each_cached_alternate(struct fetch_negotiator *negotiator,
  90                                       void (*cb)(struct fetch_negotiator *,
  91                                                  struct object *))
  92 {
  93         static int initialized;
  94         static struct alternate_object_cache cache;
  95         size_t i;
  96
  97         if (!initialized) {
  98                 for_each_alternate_ref(cache_one_alternate, &cache);
  99                 initialized = 1;
 100         }
 101
 102         for (i = 0; i < cache.nr; i++)
 103                 cb(negotiator, cache.items[i]);
 104 }
 105
 106 static int rev_list_insert_ref(struct fetch_negotiator *negotiator,
 107                                const char *refname,
 108                                const struct object_id *oid)
 109 {
 110         struct object *o = deref_tag(parse_object(oid), refname, 0);
 111
 112         if (o && o->type == OBJ_COMMIT)
 113                 negotiator->add_tip(negotiator, (struct commit *)o);
 114
 115         return 0;
 116 }
 117
 118 static int rev_list_insert_ref_oid(const char *refname, const struct object_id *oid,
 119                                    int flag, void *cb_data)
 120 {
 121         return rev_list_insert_ref(cb_data, refname, oid);
 122 }
 123
 124 enum ack_type {
 125         NAK = 0,
 126         ACK,
 127         ACK_continue,
 128         ACK_common,
 129         ACK_ready
 130 };
 131
 132 static void consume_shallow_list(struct fetch_pack_args *args, int fd)
 133 {
 134         if (args->stateless_rpc && args->deepen) {
 135                 /* If we sent a depth we will get back "duplicate"
 136                  * shallow and unshallow commands every time there
 137                  * is a block of have lines exchanged.
 138                  */
 139                 char *line;
 140                 while ((line = packet_read_line(fd, NULL))) {
 141                         if (starts_with(line, "shallow "))
 142                                 continue;
 143                         if (starts_with(line, "unshallow "))
 144                                 continue;
 145                         die(_("git fetch-pack: expected shallow list"));
 146                 }
 147         }
 148 }
 149
 150 static enum ack_type get_ack(int fd, struct object_id *result_oid)
 151 {
 152         int len;
 153         char *line = packet_read_line(fd, &len);
 154         const char *arg;
 155
 156         if (!line)
 157                 die(_("git fetch-pack: expected ACK/NAK, got a flush packet"));
 158         if (!strcmp(line, "NAK"))
 159                 return NAK;
 160         if (skip_prefix(line, "ACK ", &arg)) {
 161                 if (!get_oid_hex(arg, result_oid)) {
 162                         arg += 40;
 163                         len -= arg - line;
 164                         if (len < 1)
 165                                 return ACK;
 166                         if (strstr(arg, "continue"))
 167                                 return ACK_continue;
 168                         if (strstr(arg, "common"))
 169                                 return ACK_common;
 170                         if (strstr(arg, "ready"))
 171                                 return ACK_ready;
 172                         return ACK;
 173                 }
 174         }
 175         if (skip_prefix(line, "ERR ", &arg))
 176                 die(_("remote error: %s"), arg);
 177         die(_("git fetch-pack: expected ACK/NAK, got '%s'"), line);
 178 }
 179
 180 static void send_request(struct fetch_pack_args *args,
 181                          int fd, struct strbuf *buf)
 182 {
 183         if (args->stateless_rpc) {
 184                 send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
 185                 packet_flush(fd);
 186         } else
 187                 write_or_die(fd, buf->buf, buf->len);
 188 }
 189
 190 static void insert_one_alternate_object(struct fetch_negotiator *negotiator,
 191                                         struct object *obj)
 192 {
 193         rev_list_insert_ref(negotiator, NULL, &obj->oid);
 194 }
 195
 196 #define INITIAL_FLUSH 16
 197 #define PIPESAFE_FLUSH 32
 198 #define LARGE_FLUSH 16384
 199
 200 static int next_flush(int stateless_rpc, int count)
 201 {
 202         if (stateless_rpc) {
 203                 if (count < LARGE_FLUSH)
 204                         count <<= 1;
 205                 else
 206                         count = count * 11 / 10;
 207         } else {
 208                 if (count < PIPESAFE_FLUSH)
 209                         count <<= 1;
 210                 else
 211                         count += PIPESAFE_FLUSH;
 212         }
 213         return count;
 214 }
 215
 216 static void mark_tips(struct fetch_negotiator *negotiator,
 217                       const struct oid_array *negotiation_tips)
 218 {
 219         int i;
 220
 221         if (!negotiation_tips) {
 222                 for_each_ref(rev_list_insert_ref_oid, negotiator);
 223                 return;
 224         }
 225
 226         for (i = 0; i < negotiation_tips->nr; i++)
 227                 rev_list_insert_ref(negotiator, NULL,
 228                                     &negotiation_tips->oid[i]);
 229         return;
 230 }
 231
 232 static int find_common(struct fetch_negotiator *negotiator,
 233                        struct fetch_pack_args *args,
 234                        int fd[2], struct object_id *result_oid,
 235                        struct ref *refs)
 236 {
 237         int fetching;
 238         int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval;
 239         const struct object_id *oid;
 240         unsigned in_vain = 0;
 241         int got_continue = 0;
 242         int got_ready = 0;
 243         struct strbuf req_buf = STRBUF_INIT;
 244         size_t state_len = 0;
 245
 246         if (args->stateless_rpc && multi_ack == 1)
 247                 die(_("--stateless-rpc requires multi_ack_detailed"));
 248
 249         mark_tips(negotiator, args->negotiation_tips);
 250         for_each_cached_alternate(negotiator, insert_one_alternate_object);
 251
 252         fetching = 0;
 253         for ( ; refs ; refs = refs->next) {
 254                 struct object_id *remote = &refs->old_oid;
 255                 const char *remote_hex;
 256                 struct object *o;
 257
 258                 /*
 259                  * If that object is complete (i.e. it is an ancestor of a
 260                  * local ref), we tell them we have it but do not have to
 261                  * tell them about its ancestors, which they already know
 262                  * about.
 263                  *
 264                  * We use lookup_object here because we are only
 265                  * interested in the case we *know* the object is
 266                  * reachable and we have already scanned it.
 267                  */
 268                 if (((o = lookup_object(remote->hash)) != NULL) &&
 269                                 (o->flags & COMPLETE)) {
 270                         continue;
 271                 }
 272
 273                 remote_hex = oid_to_hex(remote);
 274                 if (!fetching) {
 275                         struct strbuf c = STRBUF_INIT;
 276                         if (multi_ack == 2)     strbuf_addstr(&c, " multi_ack_detailed");
 277                         if (multi_ack == 1)     strbuf_addstr(&c, " multi_ack");
 278                         if (no_done)            strbuf_addstr(&c, " no-done");
 279                         if (use_sideband == 2)  strbuf_addstr(&c, " side-band-64k");
 280                         if (use_sideband == 1)  strbuf_addstr(&c, " side-band");
 281                         if (args->deepen_relative) strbuf_addstr(&c, " deepen-relative");
 282                         if (args->use_thin_pack) strbuf_addstr(&c, " thin-pack");
 283                         if (args->no_progress)   strbuf_addstr(&c, " no-progress");
 284                         if (args->include_tag)   strbuf_addstr(&c, " include-tag");
 285                         if (prefer_ofs_delta)   strbuf_addstr(&c, " ofs-delta");
 286                         if (deepen_since_ok)    strbuf_addstr(&c, " deepen-since");
 287                         if (deepen_not_ok)      strbuf_addstr(&c, " deepen-not");
 288                         if (agent_supported)    strbuf_addf(&c, " agent=%s",
 289                                                             git_user_agent_sanitized());
 290                         if (args->filter_options.choice)
 291                                 strbuf_addstr(&c, " filter");
 292                         packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
 293                         strbuf_release(&c);
 294                 } else
 295                         packet_buf_write(&req_buf, "want %s\n", remote_hex);
 296                 fetching++;
 297         }
 298
 299         if (!fetching) {
 300                 strbuf_release(&req_buf);
 301                 packet_flush(fd[1]);
 302                 return 1;
 303         }
 304
 305         if (is_repository_shallow())
 306                 write_shallow_commits(&req_buf, 1, NULL);
 307         if (args->depth > 0)
 308                 packet_buf_write(&req_buf, "deepen %d", args->depth);
 309         if (args->deepen_since) {
 310                 timestamp_t max_age = approxidate(args->deepen_since);
 311                 packet_buf_write(&req_buf, "deepen-since %"PRItime, max_age);
 312         }
 313         if (args->deepen_not) {
 314                 int i;
 315                 for (i = 0; i < args->deepen_not->nr; i++) {
 316                         struct string_list_item *s = args->deepen_not->items + i;
 317                         packet_buf_write(&req_buf, "deepen-not %s", s->string);
 318                 }
 319         }
 320         if (server_supports_filtering && args->filter_options.choice)
 321                 packet_buf_write(&req_buf, "filter %s",
 322                                  args->filter_options.filter_spec);
 323         packet_buf_flush(&req_buf);
 324         state_len = req_buf.len;
 325
 326         if (args->deepen) {
 327                 char *line;
 328                 const char *arg;
 329                 struct object_id oid;
 330
 331                 send_request(args, fd[1], &req_buf);
 332                 while ((line = packet_read_line(fd[0], NULL))) {
 333                         if (skip_prefix(line, "shallow ", &arg)) {
 334                                 if (get_oid_hex(arg, &oid))
 335                                         die(_("invalid shallow line: %s"), line);
 336                                 register_shallow(&oid);
 337                                 continue;
 338                         }
 339                         if (skip_prefix(line, "unshallow ", &arg)) {
 340                                 if (get_oid_hex(arg, &oid))
 341                                         die(_("invalid unshallow line: %s"), line);
 342                                 if (!lookup_object(oid.hash))
 343                                         die(_("object not found: %s"), line);
 344                                 /* make sure that it is parsed as shallow */
 345                                 if (!parse_object(&oid))
 346                                         die(_("error in object: %s"), line);
 347                                 if (unregister_shallow(&oid))
 348                                         die(_("no shallow found: %s"), line);
 349                                 continue;
 350                         }
 351                         die(_("expected shallow/unshallow, got %s"), line);
 352                 }
 353         } else if (!args->stateless_rpc)
 354                 send_request(args, fd[1], &req_buf);
 355
 356         if (!args->stateless_rpc) {
 357                 /* If we aren't using the stateless-rpc interface
 358                  * we don't need to retain the headers.
 359                  */
 360                 strbuf_setlen(&req_buf, 0);
 361                 state_len = 0;
 362         }
 363
 364         flushes = 0;
 365         retval = -1;
 366         if (args->no_dependents)
 367                 goto done;
 368         while ((oid = negotiator->next(negotiator))) {
 369                 packet_buf_write(&req_buf, "have %s\n", oid_to_hex(oid));
 370                 print_verbose(args, "have %s", oid_to_hex(oid));
 371                 in_vain++;
 372                 if (flush_at <= ++count) {
 373                         int ack;
 374
 375                         packet_buf_flush(&req_buf);
 376                         send_request(args, fd[1], &req_buf);
 377                         strbuf_setlen(&req_buf, state_len);
 378                         flushes++;
 379                         flush_at = next_flush(args->stateless_rpc, count);
 380
 381                         /*
 382                          * We keep one window "ahead" of the other side, and
 383                          * will wait for an ACK only on the next one
 384                          */
 385                         if (!args->stateless_rpc && count == INITIAL_FLUSH)
 386                                 continue;
 387
 388                         consume_shallow_list(args, fd[0]);
 389                         do {
 390                                 ack = get_ack(fd[0], result_oid);
 391                                 if (ack)
 392                                         print_verbose(args, _("got %s %d %s"), "ack",
 393                                                       ack, oid_to_hex(result_oid));
 394                                 switch (ack) {
 395                                 case ACK:
 396                                         flushes = 0;
 397                                         multi_ack = 0;
 398                                         retval = 0;
 399                                         goto done;
 400                                 case ACK_common:
 401                                 case ACK_ready:
 402                                 case ACK_continue: {
 403                                         struct commit *commit =
 404                                                 lookup_commit(result_oid);
 405                                         int was_common;
 406                                         if (!commit)
 407                                                 die(_("invalid commit %s"), oid_to_hex(result_oid));
 408                                         was_common = negotiator->ack(negotiator, commit);
 409                                         if (args->stateless_rpc
 410                                          && ack == ACK_common
 411                                          && !was_common) {
 412                                                 /* We need to replay the have for this object
 413                                                  * on the next RPC request so the peer knows
 414                                                  * it is in common with us.
 415                                                  */
 416                                                 const char *hex = oid_to_hex(result_oid);
 417                                                 packet_buf_write(&req_buf, "have %s\n", hex);
 418                                                 state_len = req_buf.len;
 419                                                 /*
 420                                                  * Reset in_vain because an ack
 421                                                  * for this commit has not been
 422                                                  * seen.
 423                                                  */
 424                                                 in_vain = 0;
 425                                         } else if (!args->stateless_rpc
 426                                                    || ack != ACK_common)
 427                                                 in_vain = 0;
 428                                         retval = 0;
 429                                         got_continue = 1;
 430                                         if (ack == ACK_ready)
 431                                                 got_ready = 1;
 432                                         break;
 433                                         }
 434                                 }
 435                         } while (ack);
 436                         flushes--;
 437                         if (got_continue && MAX_IN_VAIN < in_vain) {
 438                                 print_verbose(args, _("giving up"));
 439                                 break; /* give up */
 440                         }
 441                         if (got_ready)
 442                                 break;
 443                 }
 444         }
 445 done:
 446         if (!got_ready || !no_done) {
 447                 packet_buf_write(&req_buf, "done\n");
 448                 send_request(args, fd[1], &req_buf);
 449         }
 450         print_verbose(args, _("done"));
 451         if (retval != 0) {
 452                 multi_ack = 0;
 453                 flushes++;
 454         }
 455         strbuf_release(&req_buf);
 456
 457         if (!got_ready || !no_done)
 458                 consume_shallow_list(args, fd[0]);
 459         while (flushes || multi_ack) {
 460                 int ack = get_ack(fd[0], result_oid);
 461                 if (ack) {
 462                         print_verbose(args, _("got %s (%d) %s"), "ack",
 463                                       ack, oid_to_hex(result_oid));
 464                         if (ack == ACK)
 465                                 return 0;
 466                         multi_ack = 1;
 467                         continue;
 468                 }
 469                 flushes--;
 470         }
 471         /* it is no error to fetch into a completely empty repo */
 472         return count ? retval : 0;
 473 }
 474
 475 static struct commit_list *complete;
 476
 477 static int mark_complete(const struct object_id *oid)
 478 {
 479         struct object *o = parse_object(oid);
 480
 481         while (o && o->type == OBJ_TAG) {
 482                 struct tag *t = (struct tag *) o;
 483                 if (!t->tagged)
 484                         break; /* broken repository */
 485                 o->flags |= COMPLETE;
 486                 o = parse_object(&t->tagged->oid);
 487         }
 488         if (o && o->type == OBJ_COMMIT) {
 489                 struct commit *commit = (struct commit *)o;
 490                 if (!(commit->object.flags & COMPLETE)) {
 491                         commit->object.flags |= COMPLETE;
 492                         commit_list_insert(commit, &complete);
 493                 }
 494         }
 495         return 0;
 496 }
 497
 498 static int mark_complete_oid(const char *refname, const struct object_id *oid,
 499                              int flag, void *cb_data)
 500 {
 501         return mark_complete(oid);
 502 }
 503
 504 static void mark_recent_complete_commits(struct fetch_pack_args *args,
 505                                          timestamp_t cutoff)
 506 {
 507         while (complete && cutoff <= complete->item->date) {
 508                 print_verbose(args, _("Marking %s as complete"),
 509                               oid_to_hex(&complete->item->object.oid));
 510                 pop_most_recent_commit(&complete, COMPLETE);
 511         }
 512 }
 513
 514 static void add_refs_to_oidset(struct oidset *oids, struct ref *refs)
 515 {
 516         for (; refs; refs = refs->next)
 517                 oidset_insert(oids, &refs->old_oid);
 518 }
 519
 520 static int tip_oids_contain(struct oidset *tip_oids,
 521                             struct ref *unmatched, struct ref *newlist,
 522                             const struct object_id *id)
 523 {
 524         /*
 525          * Note that this only looks at the ref lists the first time it's
 526          * called. This works out in filter_refs() because even though it may
 527          * add to "newlist" between calls, the additions will always be for
 528          * oids that are already in the set.
 529          */
 530         if (!tip_oids->map.map.tablesize) {
 531                 add_refs_to_oidset(tip_oids, unmatched);
 532                 add_refs_to_oidset(tip_oids, newlist);
 533         }
 534         return oidset_contains(tip_oids, id);
 535 }
 536
 537 static void filter_refs(struct fetch_pack_args *args,
 538                         struct ref **refs,
 539                         struct ref **sought, int nr_sought)
 540 {
 541         struct ref *newlist = NULL;
 542         struct ref **newtail = &newlist;
 543         struct ref *unmatched = NULL;
 544         struct ref *ref, *next;
 545         struct oidset tip_oids = OIDSET_INIT;
 546         int i;
 547
 548         i = 0;
 549         for (ref = *refs; ref; ref = next) {
 550                 int keep = 0;
 551                 next = ref->next;
 552
 553                 if (starts_with(ref->name, "refs/") &&
 554                     check_refname_format(ref->name, 0))
 555                         ; /* trash */
 556                 else {
 557                         while (i < nr_sought) {
 558                                 int cmp = strcmp(ref->name, sought[i]->name);
 559                                 if (cmp < 0)
 560                                         break; /* definitely do not have it */
 561                                 else if (cmp == 0) {
 562                                         keep = 1; /* definitely have it */
 563                                         sought[i]->match_status = REF_MATCHED;
 564                                 }
 565                                 i++;
 566                         }
 567                 }
 568
 569                 if (!keep && args->fetch_all &&
 570                     (!args->deepen || !starts_with(ref->name, "refs/tags/")))
 571                         keep = 1;
 572
 573                 if (keep) {
 574                         *newtail = ref;
 575                         ref->next = NULL;
 576                         newtail = &ref->next;
 577                 } else {
 578                         ref->next = unmatched;
 579                         unmatched = ref;
 580                 }
 581         }
 582
 583         /* Append unmatched requests to the list */
 584         for (i = 0; i < nr_sought; i++) {
 585                 struct object_id oid;
 586                 const char *p;
 587
 588                 ref = sought[i];
 589                 if (ref->match_status != REF_NOT_MATCHED)
 590                         continue;
 591                 if (parse_oid_hex(ref->name, &oid, &p) ||
 592                     *p != '\0' ||
 593                     oidcmp(&oid, &ref->old_oid))
 594                         continue;
 595
 596                 if ((allow_unadvertised_object_request &
 597                      (ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1)) ||
 598                     tip_oids_contain(&tip_oids, unmatched, newlist,
 599                                      &ref->old_oid)) {
 600                         ref->match_status = REF_MATCHED;
 601                         *newtail = copy_ref(ref);
 602                         newtail = &(*newtail)->next;
 603                 } else {
 604                         ref->match_status = REF_UNADVERTISED_NOT_ALLOWED;
 605                 }
 606         }
 607
 608         oidset_clear(&tip_oids);
 609         for (ref = unmatched; ref; ref = next) {
 610                 next = ref->next;
 611                 free(ref);
 612         }
 613
 614         *refs = newlist;
 615 }
 616
 617 static void mark_alternate_complete(struct fetch_negotiator *unused,
 618                                     struct object *obj)
 619 {
 620         mark_complete(&obj->oid);
 621 }
 622
 623 struct loose_object_iter {
 624         struct oidset *loose_object_set;
 625         struct ref *refs;
 626 };
 627
 628 /*
 629  *  If the number of refs is not larger than the number of loose objects,
 630  *  this function stops inserting.
 631  */
 632 static int add_loose_objects_to_set(const struct object_id *oid,
 633                                     const char *path,
 634                                     void *data)
 635 {
 636         struct loose_object_iter *iter = data;
 637         oidset_insert(iter->loose_object_set, oid);
 638         if (iter->refs == NULL)
 639                 return 1;
 640
 641         iter->refs = iter->refs->next;
 642         return 0;
 643 }
 644
 645 /*
 646  * Mark recent commits available locally and reachable from a local ref as
 647  * COMPLETE. If args->no_dependents is false, also mark COMPLETE remote refs as
 648  * COMMON_REF (otherwise, we are not planning to participate in negotiation, and
 649  * thus do not need COMMON_REF marks).
 650  *
 651  * The cutoff time for recency is determined by this heuristic: it is the
 652  * earliest commit time of the objects in refs that are commits and that we know
 653  * the commit time of.
 654  */
 655 static void mark_complete_and_common_ref(struct fetch_negotiator *negotiator,
 656                                          struct fetch_pack_args *args,
 657                                          struct ref **refs)
 658 {
 659         struct ref *ref;
 660         int old_save_commit_buffer = save_commit_buffer;
 661         timestamp_t cutoff = 0;
 662         struct oidset loose_oid_set = OIDSET_INIT;
 663         int use_oidset = 0;
 664         struct loose_object_iter iter = {&loose_oid_set, *refs};
 665
 666         /* Enumerate all loose objects or know refs are not so many. */
 667         use_oidset = !for_each_loose_object(add_loose_objects_to_set,
 668                                             &iter, 0);
 669
 670         save_commit_buffer = 0;
 671
 672         for (ref = *refs; ref; ref = ref->next) {
 673                 struct object *o;
 674                 unsigned int flags = OBJECT_INFO_QUICK;
 675
 676                 if (use_oidset &&
 677                     !oidset_contains(&loose_oid_set, &ref->old_oid)) {
 678                         /*
 679                          * I know this does not exist in the loose form,
 680                          * so check if it exists in a non-loose form.
 681                          */
 682                         flags |= OBJECT_INFO_IGNORE_LOOSE;
 683                 }
 684
 685                 if (!has_object_file_with_flags(&ref->old_oid, flags))
 686                         continue;
 687                 o = parse_object(&ref->old_oid);
 688                 if (!o)
 689                         continue;
 690
 691                 /* We already have it -- which may mean that we were
 692                  * in sync with the other side at some time after
 693                  * that (it is OK if we guess wrong here).
 694                  */
 695                 if (o->type == OBJ_COMMIT) {
 696                         struct commit *commit = (struct commit *)o;
 697                         if (!cutoff || cutoff < commit->date)
 698                                 cutoff = commit->date;
 699                 }
 700         }
 701
 702         oidset_clear(&loose_oid_set);
 703
 704         if (!args->no_dependents) {
 705                 if (!args->deepen) {
 706                         for_each_ref(mark_complete_oid, NULL);
 707                         for_each_cached_alternate(NULL, mark_alternate_complete);
 708                         commit_list_sort_by_date(&complete);
 709                         if (cutoff)
 710                                 mark_recent_complete_commits(args, cutoff);
 711                 }
 712
 713                 /*
 714                  * Mark all complete remote refs as common refs.
 715                  * Don't mark them common yet; the server has to be told so first.
 716                  */
 717                 for (ref = *refs; ref; ref = ref->next) {
 718                         struct object *o = deref_tag(lookup_object(ref->old_oid.hash),
 719                                                      NULL, 0);
 720
 721                         if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 722                                 continue;
 723
 724                         negotiator->known_common(negotiator,
 725                                                  (struct commit *)o);
 726                 }
 727         }
 728
 729         save_commit_buffer = old_save_commit_buffer;
 730 }
 731
 732 /*
 733  * Returns 1 if every object pointed to by the given remote refs is available
 734  * locally and reachable from a local ref, and 0 otherwise.
 735  */
 736 static int everything_local(struct fetch_pack_args *args,
 737                             struct ref **refs)
 738 {
 739         struct ref *ref;
 740         int retval;
 741
 742         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 743                 const struct object_id *remote = &ref->old_oid;
 744                 struct object *o;
 745
 746                 o = lookup_object(remote->hash);
 747                 if (!o || !(o->flags & COMPLETE)) {
 748                         retval = 0;
 749                         print_verbose(args, "want %s (%s)", oid_to_hex(remote),
 750                                       ref->name);
 751                         continue;
 752                 }
 753                 print_verbose(args, _("already have %s (%s)"), oid_to_hex(remote),
 754                               ref->name);
 755         }
 756
 757         return retval;
 758 }
 759
 760 static int sideband_demux(int in, int out, void *data)
 761 {
 762         int *xd = data;
 763         int ret;
 764
 765         ret = recv_sideband("fetch-pack", xd[0], out);
 766         close(out);
 767         return ret;
 768 }
 769
 770 static int get_pack(struct fetch_pack_args *args,
 771                     int xd[2], char **pack_lockfile)
 772 {
 773         struct async demux;
 774         int do_keep = args->keep_pack;
 775         const char *cmd_name;
 776         struct pack_header header;
 777         int pass_header = 0;
 778         struct child_process cmd = CHILD_PROCESS_INIT;
 779         int ret;
 780
 781         memset(&demux, 0, sizeof(demux));
 782         if (use_sideband) {
 783                 /* xd[] is talking with upload-pack; subprocess reads from
 784                  * xd[0], spits out band#2 to stderr, and feeds us band#1
 785                  * through demux->out.
 786                  */
 787                 demux.proc = sideband_demux;
 788                 demux.data = xd;
 789                 demux.out = -1;
 790                 demux.isolate_sigpipe = 1;
 791                 if (start_async(&demux))
 792                         die(_("fetch-pack: unable to fork off sideband demultiplexer"));
 793         }
 794         else
 795                 demux.out = xd[0];
 796
 797         if (!args->keep_pack && unpack_limit) {
 798
 799                 if (read_pack_header(demux.out, &header))
 800                         die(_("protocol error: bad pack header"));
 801                 pass_header = 1;
 802                 if (ntohl(header.hdr_entries) < unpack_limit)
 803                         do_keep = 0;
 804                 else
 805                         do_keep = 1;
 806         }
 807
 808         if (alternate_shallow_file) {
 809                 argv_array_push(&cmd.args, "--shallow-file");
 810                 argv_array_push(&cmd.args, alternate_shallow_file);
 811         }
 812
 813         if (do_keep || args->from_promisor) {
 814                 if (pack_lockfile)
 815                         cmd.out = -1;
 816                 cmd_name = "index-pack";
 817                 argv_array_push(&cmd.args, cmd_name);
 818                 argv_array_push(&cmd.args, "--stdin");
 819                 if (!args->quiet && !args->no_progress)
 820                         argv_array_push(&cmd.args, "-v");
 821                 if (args->use_thin_pack)
 822                         argv_array_push(&cmd.args, "--fix-thin");
 823                 if (do_keep && (args->lock_pack || unpack_limit)) {
 824                         char hostname[HOST_NAME_MAX + 1];
 825                         if (xgethostname(hostname, sizeof(hostname)))
 826                                 xsnprintf(hostname, sizeof(hostname), "localhost");
 827                         argv_array_pushf(&cmd.args,
 828                                         "--keep=fetch-pack %"PRIuMAX " on %s",
 829                                         (uintmax_t)getpid(), hostname);
 830                 }
 831                 if (args->check_self_contained_and_connected)
 832                         argv_array_push(&cmd.args, "--check-self-contained-and-connected");
 833                 if (args->from_promisor)
 834                         argv_array_push(&cmd.args, "--promisor");
 835         }
 836         else {
 837                 cmd_name = "unpack-objects";
 838                 argv_array_push(&cmd.args, cmd_name);
 839                 if (args->quiet || args->no_progress)
 840                         argv_array_push(&cmd.args, "-q");
 841                 args->check_self_contained_and_connected = 0;
 842         }
 843
 844         if (pass_header)
 845                 argv_array_pushf(&cmd.args, "--pack_header=%"PRIu32",%"PRIu32,
 846                                  ntohl(header.hdr_version),
 847                                  ntohl(header.hdr_entries));
 848         if (fetch_fsck_objects >= 0
 849             ? fetch_fsck_objects
 850             : transfer_fsck_objects >= 0
 851             ? transfer_fsck_objects
 852             : 0) {
 853                 if (args->from_promisor)
 854                         /*
 855                          * We cannot use --strict in index-pack because it
 856                          * checks both broken objects and links, but we only
 857                          * want to check for broken objects.
 858                          */
 859                         argv_array_push(&cmd.args, "--fsck-objects");
 860                 else
 861                         argv_array_push(&cmd.args, "--strict");
 862         }
 863
 864         cmd.in = demux.out;
 865         cmd.git_cmd = 1;
 866         if (start_command(&cmd))
 867                 die(_("fetch-pack: unable to fork off %s"), cmd_name);
 868         if (do_keep && pack_lockfile) {
 869                 *pack_lockfile = index_pack_lockfile(cmd.out);
 870                 close(cmd.out);
 871         }
 872
 873         if (!use_sideband)
 874                 /* Closed by start_command() */
 875                 xd[0] = -1;
 876
 877         ret = finish_command(&cmd);
 878         if (!ret || (args->check_self_contained_and_connected && ret == 1))
 879                 args->self_contained_and_connected =
 880                         args->check_self_contained_and_connected &&
 881                         ret == 0;
 882         else
 883                 die(_("%s failed"), cmd_name);
 884         if (use_sideband && finish_async(&demux))
 885                 die(_("error in sideband demultiplexer"));
 886         return 0;
 887 }
 888
 889 static int cmp_ref_by_name(const void *a_, const void *b_)
 890 {
 891         const struct ref *a = *((const struct ref **)a_);
 892         const struct ref *b = *((const struct ref **)b_);
 893         return strcmp(a->name, b->name);
 894 }
 895
 896 static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 897                                  int fd[2],
 898                                  const struct ref *orig_ref,
 899                                  struct ref **sought, int nr_sought,
 900                                  struct shallow_info *si,
 901                                  char **pack_lockfile)
 902 {
 903         struct ref *ref = copy_ref_list(orig_ref);
 904         struct object_id oid;
 905         const char *agent_feature;
 906         int agent_len;
 907         struct fetch_negotiator negotiator;
 908         fetch_negotiator_init(&negotiator);
 909
 910         sort_ref_list(&ref, ref_compare_name);
 911         QSORT(sought, nr_sought, cmp_ref_by_name);
 912
 913         if ((args->depth > 0 || is_repository_shallow()) && !server_supports("shallow"))
 914                 die(_("Server does not support shallow clients"));
 915         if (args->depth > 0 || args->deepen_since || args->deepen_not)
 916                 args->deepen = 1;
 917         if (server_supports("multi_ack_detailed")) {
 918                 print_verbose(args, _("Server supports multi_ack_detailed"));
 919                 multi_ack = 2;
 920                 if (server_supports("no-done")) {
 921                         print_verbose(args, _("Server supports no-done"));
 922                         if (args->stateless_rpc)
 923                                 no_done = 1;
 924                 }
 925         }
 926         else if (server_supports("multi_ack")) {
 927                 print_verbose(args, _("Server supports multi_ack"));
 928                 multi_ack = 1;
 929         }
 930         if (server_supports("side-band-64k")) {
 931                 print_verbose(args, _("Server supports side-band-64k"));
 932                 use_sideband = 2;
 933         }
 934         else if (server_supports("side-band")) {
 935                 print_verbose(args, _("Server supports side-band"));
 936                 use_sideband = 1;
 937         }
 938         if (server_supports("allow-tip-sha1-in-want")) {
 939                 print_verbose(args, _("Server supports allow-tip-sha1-in-want"));
 940                 allow_unadvertised_object_request |= ALLOW_TIP_SHA1;
 941         }
 942         if (server_supports("allow-reachable-sha1-in-want")) {
 943                 print_verbose(args, _("Server supports allow-reachable-sha1-in-want"));
 944                 allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
 945         }
 946         if (!server_supports("thin-pack"))
 947                 args->use_thin_pack = 0;
 948         if (!server_supports("no-progress"))
 949                 args->no_progress = 0;
 950         if (!server_supports("include-tag"))
 951                 args->include_tag = 0;
 952         if (server_supports("ofs-delta"))
 953                 print_verbose(args, _("Server supports ofs-delta"));
 954         else
 955                 prefer_ofs_delta = 0;
 956
 957         if (server_supports("filter")) {
 958                 server_supports_filtering = 1;
 959                 print_verbose(args, _("Server supports filter"));
 960         } else if (args->filter_options.choice) {
 961                 warning("filtering not recognized by server, ignoring");
 962         }
 963
 964         if ((agent_feature = server_feature_value("agent", &agent_len))) {
 965                 agent_supported = 1;
 966                 if (agent_len)
 967                         print_verbose(args, _("Server version is %.*s"),
 968                                       agent_len, agent_feature);
 969         }
 970         if (server_supports("deepen-since"))
 971                 deepen_since_ok = 1;
 972         else if (args->deepen_since)
 973                 die(_("Server does not support --shallow-since"));
 974         if (server_supports("deepen-not"))
 975                 deepen_not_ok = 1;
 976         else if (args->deepen_not)
 977                 die(_("Server does not support --shallow-exclude"));
 978         if (!server_supports("deepen-relative") && args->deepen_relative)
 979                 die(_("Server does not support --deepen"));
 980
 981         mark_complete_and_common_ref(&negotiator, args, &ref);
 982         filter_refs(args, &ref, sought, nr_sought);
 983         if (everything_local(args, &ref)) {
 984                 packet_flush(fd[1]);
 985                 goto all_done;
 986         }
 987         if (find_common(&negotiator, args, fd, &oid, ref) < 0)
 988                 if (!args->keep_pack)
 989                         /* When cloning, it is not unusual to have
 990                          * no common commit.
 991                          */
 992                         warning(_("no common commits"));
 993
 994         if (args->stateless_rpc)
 995                 packet_flush(fd[1]);
 996         if (args->deepen)
 997                 setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
 998                                         NULL);
 999         else if (si->nr_ours || si->nr_theirs)
1000                 alternate_shallow_file = setup_temporary_shallow(si->shallow);
1001         else
1002                 alternate_shallow_file = NULL;
1003         if (get_pack(args, fd, pack_lockfile))
1004                 die(_("git fetch-pack: fetch failed."));
1005
1006  all_done:
1007         negotiator.release(&negotiator);
1008         return ref;
1009 }
1010
1011 static void add_shallow_requests(struct strbuf *req_buf,
1012                                  const struct fetch_pack_args *args)
1013 {
1014         if (is_repository_shallow())
1015                 write_shallow_commits(req_buf, 1, NULL);
1016         if (args->depth > 0)
1017                 packet_buf_write(req_buf, "deepen %d", args->depth);
1018         if (args->deepen_since) {
1019                 timestamp_t max_age = approxidate(args->deepen_since);
1020                 packet_buf_write(req_buf, "deepen-since %"PRItime, max_age);
1021         }
1022         if (args->deepen_not) {
1023                 int i;
1024                 for (i = 0; i < args->deepen_not->nr; i++) {
1025                         struct string_list_item *s = args->deepen_not->items + i;
1026                         packet_buf_write(req_buf, "deepen-not %s", s->string);
1027                 }
1028         }
1029 }
1030
1031 static void add_wants(const struct ref *wants, struct strbuf *req_buf)
1032 {
1033         for ( ; wants ; wants = wants->next) {
1034                 const struct object_id *remote = &wants->old_oid;
1035                 const char *remote_hex;
1036                 struct object *o;
1037
1038                 /*
1039                  * If that object is complete (i.e. it is an ancestor of a
1040                  * local ref), we tell them we have it but do not have to
1041                  * tell them about its ancestors, which they already know
1042                  * about.
1043                  *
1044                  * We use lookup_object here because we are only
1045                  * interested in the case we *know* the object is
1046                  * reachable and we have already scanned it.
1047                  */
1048                 if (((o = lookup_object(remote->hash)) != NULL) &&
1049                     (o->flags & COMPLETE)) {
1050                         continue;
1051                 }
1052
1053                 remote_hex = oid_to_hex(remote);
1054                 packet_buf_write(req_buf, "want %s\n", remote_hex);
1055         }
1056 }
1057
1058 static void add_common(struct strbuf *req_buf, struct oidset *common)
1059 {
1060         struct oidset_iter iter;
1061         const struct object_id *oid;
1062         oidset_iter_init(common, &iter);
1063
1064         while ((oid = oidset_iter_next(&iter))) {
1065                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1066         }
1067 }
1068
1069 static int add_haves(struct fetch_negotiator *negotiator,
1070                      struct strbuf *req_buf,
1071                      int *haves_to_send, int *in_vain)
1072 {
1073         int ret = 0;
1074         int haves_added = 0;
1075         const struct object_id *oid;
1076
1077         while ((oid = negotiator->next(negotiator))) {
1078                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1079                 if (++haves_added >= *haves_to_send)
1080                         break;
1081         }
1082
1083         *in_vain += haves_added;
1084         if (!haves_added || *in_vain >= MAX_IN_VAIN) {
1085                 /* Send Done */
1086                 packet_buf_write(req_buf, "done\n");
1087                 ret = 1;
1088         }
1089
1090         /* Increase haves to send on next round */
1091         *haves_to_send = next_flush(1, *haves_to_send);
1092
1093         return ret;
1094 }
1095
1096 static int send_fetch_request(struct fetch_negotiator *negotiator, int fd_out,
1097                               const struct fetch_pack_args *args,
1098                               const struct ref *wants, struct oidset *common,
1099                               int *haves_to_send, int *in_vain)
1100 {
1101         int ret = 0;
1102         struct strbuf req_buf = STRBUF_INIT;
1103
1104         if (server_supports_v2("fetch", 1))
1105                 packet_buf_write(&req_buf, "command=fetch");
1106         if (server_supports_v2("agent", 0))
1107                 packet_buf_write(&req_buf, "agent=%s", git_user_agent_sanitized());
1108         if (args->server_options && args->server_options->nr &&
1109             server_supports_v2("server-option", 1)) {
1110                 int i;
1111                 for (i = 0; i < args->server_options->nr; i++)
1112                         packet_write_fmt(fd_out, "server-option=%s",
1113                                          args->server_options->items[i].string);
1114         }
1115
1116         packet_buf_delim(&req_buf);
1117         if (args->use_thin_pack)
1118                 packet_buf_write(&req_buf, "thin-pack");
1119         if (args->no_progress)
1120                 packet_buf_write(&req_buf, "no-progress");
1121         if (args->include_tag)
1122                 packet_buf_write(&req_buf, "include-tag");
1123         if (prefer_ofs_delta)
1124                 packet_buf_write(&req_buf, "ofs-delta");
1125
1126         /* Add shallow-info and deepen request */
1127         if (server_supports_feature("fetch", "shallow", 0))
1128                 add_shallow_requests(&req_buf, args);
1129         else if (is_repository_shallow() || args->deepen)
1130                 die(_("Server does not support shallow requests"));
1131
1132         /* Add filter */
1133         if (server_supports_feature("fetch", "filter", 0) &&
1134             args->filter_options.choice) {
1135                 print_verbose(args, _("Server supports filter"));
1136                 packet_buf_write(&req_buf, "filter %s",
1137                                  args->filter_options.filter_spec);
1138         } else if (args->filter_options.choice) {
1139                 warning("filtering not recognized by server, ignoring");
1140         }
1141
1142         /* add wants */
1143         add_wants(wants, &req_buf);
1144
1145         if (args->no_dependents) {
1146                 packet_buf_write(&req_buf, "done");
1147                 ret = 1;
1148         } else {
1149                 /* Add all of the common commits we've found in previous rounds */
1150                 add_common(&req_buf, common);
1151
1152                 /* Add initial haves */
1153                 ret = add_haves(negotiator, &req_buf, haves_to_send, in_vain);
1154         }
1155
1156         /* Send request */
1157         packet_buf_flush(&req_buf);
1158         write_or_die(fd_out, req_buf.buf, req_buf.len);
1159
1160         strbuf_release(&req_buf);
1161         return ret;
1162 }
1163
1164 /*
1165  * Processes a section header in a server's response and checks if it matches
1166  * `section`.  If the value of `peek` is 1, the header line will be peeked (and
1167  * not consumed); if 0, the line will be consumed and the function will die if
1168  * the section header doesn't match what was expected.
1169  */
1170 static int process_section_header(struct packet_reader *reader,
1171                                   const char *section, int peek)
1172 {
1173         int ret;
1174
1175         if (packet_reader_peek(reader) != PACKET_READ_NORMAL)
1176                 die("error reading section header '%s'", section);
1177
1178         ret = !strcmp(reader->line, section);
1179
1180         if (!peek) {
1181                 if (!ret)
1182                         die("expected '%s', received '%s'",
1183                             section, reader->line);
1184                 packet_reader_read(reader);
1185         }
1186
1187         return ret;
1188 }
1189
1190 static int process_acks(struct fetch_negotiator *negotiator,
1191                         struct packet_reader *reader,
1192                         struct oidset *common)
1193 {
1194         /* received */
1195         int received_ready = 0;
1196         int received_ack = 0;
1197
1198         process_section_header(reader, "acknowledgments", 0);
1199         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1200                 const char *arg;
1201
1202                 if (!strcmp(reader->line, "NAK"))
1203                         continue;
1204
1205                 if (skip_prefix(reader->line, "ACK ", &arg)) {
1206                         struct object_id oid;
1207                         if (!get_oid_hex(arg, &oid)) {
1208                                 struct commit *commit;
1209                                 oidset_insert(common, &oid);
1210                                 commit = lookup_commit(&oid);
1211                                 negotiator->ack(negotiator, commit);
1212                         }
1213                         continue;
1214                 }
1215
1216                 if (!strcmp(reader->line, "ready")) {
1217                         received_ready = 1;
1218                         continue;
1219                 }
1220
1221                 die("unexpected acknowledgment line: '%s'", reader->line);
1222         }
1223
1224         if (reader->status != PACKET_READ_FLUSH &&
1225             reader->status != PACKET_READ_DELIM)
1226                 die("error processing acks: %d", reader->status);
1227
1228         /* return 0 if no common, 1 if there are common, or 2 if ready */
1229         return received_ready ? 2 : (received_ack ? 1 : 0);
1230 }
1231
1232 static void receive_shallow_info(struct fetch_pack_args *args,
1233                                  struct packet_reader *reader)
1234 {
1235         process_section_header(reader, "shallow-info", 0);
1236         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1237                 const char *arg;
1238                 struct object_id oid;
1239
1240                 if (skip_prefix(reader->line, "shallow ", &arg)) {
1241                         if (get_oid_hex(arg, &oid))
1242                                 die(_("invalid shallow line: %s"), reader->line);
1243                         register_shallow(&oid);
1244                         continue;
1245                 }
1246                 if (skip_prefix(reader->line, "unshallow ", &arg)) {
1247                         if (get_oid_hex(arg, &oid))
1248                                 die(_("invalid unshallow line: %s"), reader->line);
1249                         if (!lookup_object(oid.hash))
1250                                 die(_("object not found: %s"), reader->line);
1251                         /* make sure that it is parsed as shallow */
1252                         if (!parse_object(&oid))
1253                                 die(_("error in object: %s"), reader->line);
1254                         if (unregister_shallow(&oid))
1255                                 die(_("no shallow found: %s"), reader->line);
1256                         continue;
1257                 }
1258                 die(_("expected shallow/unshallow, got %s"), reader->line);
1259         }
1260
1261         if (reader->status != PACKET_READ_FLUSH &&
1262             reader->status != PACKET_READ_DELIM)
1263                 die("error processing shallow info: %d", reader->status);
1264
1265         setup_alternate_shallow(&shallow_lock, &alternate_shallow_file, NULL);
1266         args->deepen = 1;
1267 }
1268
1269 enum fetch_state {
1270         FETCH_CHECK_LOCAL = 0,
1271         FETCH_SEND_REQUEST,
1272         FETCH_PROCESS_ACKS,
1273         FETCH_GET_PACK,
1274         FETCH_DONE,
1275 };
1276
1277 static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
1278                                     int fd[2],
1279                                     const struct ref *orig_ref,
1280                                     struct ref **sought, int nr_sought,
1281                                     char **pack_lockfile)
1282 {
1283         struct ref *ref = copy_ref_list(orig_ref);
1284         enum fetch_state state = FETCH_CHECK_LOCAL;
1285         struct oidset common = OIDSET_INIT;
1286         struct packet_reader reader;
1287         int in_vain = 0;
1288         int haves_to_send = INITIAL_FLUSH;
1289         struct fetch_negotiator negotiator;
1290         fetch_negotiator_init(&negotiator);
1291         packet_reader_init(&reader, fd[0], NULL, 0,
1292                            PACKET_READ_CHOMP_NEWLINE);
1293
1294         while (state != FETCH_DONE) {
1295                 switch (state) {
1296                 case FETCH_CHECK_LOCAL:
1297                         sort_ref_list(&ref, ref_compare_name);
1298                         QSORT(sought, nr_sought, cmp_ref_by_name);
1299
1300                         /* v2 supports these by default */
1301                         allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
1302                         use_sideband = 2;
1303                         if (args->depth > 0 || args->deepen_since || args->deepen_not)
1304                                 args->deepen = 1;
1305
1306                         /* Filter 'ref' by 'sought' and those that aren't local */
1307                         mark_complete_and_common_ref(&negotiator, args, &ref);
1308                         filter_refs(args, &ref, sought, nr_sought);
1309                         if (everything_local(args, &ref))
1310                                 state = FETCH_DONE;
1311                         else
1312                                 state = FETCH_SEND_REQUEST;
1313
1314                         mark_tips(&negotiator, args->negotiation_tips);
1315                         for_each_cached_alternate(&negotiator,
1316                                                   insert_one_alternate_object);
1317                         break;
1318                 case FETCH_SEND_REQUEST:
1319                         if (send_fetch_request(&negotiator, fd[1], args, ref,
1320                                                &common,
1321                                                &haves_to_send, &in_vain))
1322                                 state = FETCH_GET_PACK;
1323                         else
1324                                 state = FETCH_PROCESS_ACKS;
1325                         break;
1326                 case FETCH_PROCESS_ACKS:
1327                         /* Process ACKs/NAKs */
1328                         switch (process_acks(&negotiator, &reader, &common)) {
1329                         case 2:
1330                                 state = FETCH_GET_PACK;
1331                                 break;
1332                         case 1:
1333                                 in_vain = 0;
1334                                 /* fallthrough */
1335                         default:
1336                                 state = FETCH_SEND_REQUEST;
1337                                 break;
1338                         }
1339                         break;
1340                 case FETCH_GET_PACK:
1341                         /* Check for shallow-info section */
1342                         if (process_section_header(&reader, "shallow-info", 1))
1343                                 receive_shallow_info(args, &reader);
1344
1345                         /* get the pack */
1346                         process_section_header(&reader, "packfile", 0);
1347                         if (get_pack(args, fd, pack_lockfile))
1348                                 die(_("git fetch-pack: fetch failed."));
1349
1350                         state = FETCH_DONE;
1351                         break;
1352                 case FETCH_DONE:
1353                         continue;
1354                 }
1355         }
1356
1357         negotiator.release(&negotiator);
1358         oidset_clear(&common);
1359         return ref;
1360 }
1361
1362 static void fetch_pack_config(void)
1363 {
1364         git_config_get_int("fetch.unpacklimit", &fetch_unpack_limit);
1365         git_config_get_int("transfer.unpacklimit", &transfer_unpack_limit);
1366         git_config_get_bool("repack.usedeltabaseoffset", &prefer_ofs_delta);
1367         git_config_get_bool("fetch.fsckobjects", &fetch_fsck_objects);
1368         git_config_get_bool("transfer.fsckobjects", &transfer_fsck_objects);
1369
1370         git_config(git_default_config, NULL);
1371 }
1372
1373 static void fetch_pack_setup(void)
1374 {
1375         static int did_setup;
1376         if (did_setup)
1377                 return;
1378         fetch_pack_config();
1379         if (0 <= transfer_unpack_limit)
1380                 unpack_limit = transfer_unpack_limit;
1381         else if (0 <= fetch_unpack_limit)
1382                 unpack_limit = fetch_unpack_limit;
1383         did_setup = 1;
1384 }
1385
1386 static int remove_duplicates_in_refs(struct ref **ref, int nr)
1387 {
1388         struct string_list names = STRING_LIST_INIT_NODUP;
1389         int src, dst;
1390
1391         for (src = dst = 0; src < nr; src++) {
1392                 struct string_list_item *item;
1393                 item = string_list_insert(&names, ref[src]->name);
1394                 if (item->util)
1395                         continue; /* already have it */
1396                 item->util = ref[src];
1397                 if (src != dst)
1398                         ref[dst] = ref[src];
1399                 dst++;
1400         }
1401         for (src = dst; src < nr; src++)
1402                 ref[src] = NULL;
1403         string_list_clear(&names, 0);
1404         return dst;
1405 }
1406
1407 static void update_shallow(struct fetch_pack_args *args,
1408                            struct ref **sought, int nr_sought,
1409                            struct shallow_info *si)
1410 {
1411         struct oid_array ref = OID_ARRAY_INIT;
1412         int *status;
1413         int i;
1414
1415         if (args->deepen && alternate_shallow_file) {
1416                 if (*alternate_shallow_file == '\0') { /* --unshallow */
1417                         unlink_or_warn(git_path_shallow());
1418                         rollback_lock_file(&shallow_lock);
1419                 } else
1420                         commit_lock_file(&shallow_lock);
1421                 return;
1422         }
1423
1424         if (!si->shallow || !si->shallow->nr)
1425                 return;
1426
1427         if (args->cloning) {
1428                 /*
1429                  * remote is shallow, but this is a clone, there are
1430                  * no objects in repo to worry about. Accept any
1431                  * shallow points that exist in the pack (iow in repo
1432                  * after get_pack() and reprepare_packed_git())
1433                  */
1434                 struct oid_array extra = OID_ARRAY_INIT;
1435                 struct object_id *oid = si->shallow->oid;
1436                 for (i = 0; i < si->shallow->nr; i++)
1437                         if (has_object_file(&oid[i]))
1438                                 oid_array_append(&extra, &oid[i]);
1439                 if (extra.nr) {
1440                         setup_alternate_shallow(&shallow_lock,
1441                                                 &alternate_shallow_file,
1442                                                 &extra);
1443                         commit_lock_file(&shallow_lock);
1444                 }
1445                 oid_array_clear(&extra);
1446                 return;
1447         }
1448
1449         if (!si->nr_ours && !si->nr_theirs)
1450                 return;
1451
1452         remove_nonexistent_theirs_shallow(si);
1453         if (!si->nr_ours && !si->nr_theirs)
1454                 return;
1455         for (i = 0; i < nr_sought; i++)
1456                 oid_array_append(&ref, &sought[i]->old_oid);
1457         si->ref = &ref;
1458
1459         if (args->update_shallow) {
1460                 /*
1461                  * remote is also shallow, .git/shallow may be updated
1462                  * so all refs can be accepted. Make sure we only add
1463                  * shallow roots that are actually reachable from new
1464                  * refs.
1465                  */
1466                 struct oid_array extra = OID_ARRAY_INIT;
1467                 struct object_id *oid = si->shallow->oid;
1468                 assign_shallow_commits_to_refs(si, NULL, NULL);
1469                 if (!si->nr_ours && !si->nr_theirs) {
1470                         oid_array_clear(&ref);
1471                         return;
1472                 }
1473                 for (i = 0; i < si->nr_ours; i++)
1474                         oid_array_append(&extra, &oid[si->ours[i]]);
1475                 for (i = 0; i < si->nr_theirs; i++)
1476                         oid_array_append(&extra, &oid[si->theirs[i]]);
1477                 setup_alternate_shallow(&shallow_lock,
1478                                         &alternate_shallow_file,
1479                                         &extra);
1480                 commit_lock_file(&shallow_lock);
1481                 oid_array_clear(&extra);
1482                 oid_array_clear(&ref);
1483                 return;
1484         }
1485
1486         /*
1487          * remote is also shallow, check what ref is safe to update
1488          * without updating .git/shallow
1489          */
1490         status = xcalloc(nr_sought, sizeof(*status));
1491         assign_shallow_commits_to_refs(si, NULL, status);
1492         if (si->nr_ours || si->nr_theirs) {
1493                 for (i = 0; i < nr_sought; i++)
1494                         if (status[i])
1495                                 sought[i]->status = REF_STATUS_REJECT_SHALLOW;
1496         }
1497         free(status);
1498         oid_array_clear(&ref);
1499 }
1500
1501 struct ref *fetch_pack(struct fetch_pack_args *args,
1502                        int fd[], struct child_process *conn,
1503                        const struct ref *ref,
1504                        const char *dest,
1505                        struct ref **sought, int nr_sought,
1506                        struct oid_array *shallow,
1507                        char **pack_lockfile,
1508                        enum protocol_version version)
1509 {
1510         struct ref *ref_cpy;
1511         struct shallow_info si;
1512
1513         fetch_pack_setup();
1514         if (nr_sought)
1515                 nr_sought = remove_duplicates_in_refs(sought, nr_sought);
1516
1517         if (!ref) {
1518                 packet_flush(fd[1]);
1519                 die(_("no matching remote head"));
1520         }
1521         prepare_shallow_info(&si, shallow);
1522         if (version == protocol_v2)
1523                 ref_cpy = do_fetch_pack_v2(args, fd, ref, sought, nr_sought,
1524                                            pack_lockfile);
1525         else
1526                 ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
1527                                         &si, pack_lockfile);
1528         reprepare_packed_git(the_repository);
1529         update_shallow(args, sought, nr_sought, &si);
1530         clear_shallow_info(&si);
1531         return ref_cpy;
1532 }
1533
1534 int report_unmatched_refs(struct ref **sought, int nr_sought)
1535 {
1536         int i, ret = 0;
1537
1538         for (i = 0; i < nr_sought; i++) {
1539                 if (!sought[i])
1540                         continue;
1541                 switch (sought[i]->match_status) {
1542                 case REF_MATCHED:
1543                         continue;
1544                 case REF_NOT_MATCHED:
1545                         error(_("no such remote ref %s"), sought[i]->name);
1546                         break;
1547                 case REF_UNADVERTISED_NOT_ALLOWED:
1548                         error(_("Server does not allow request for unadvertised object %s"),
1549                               sought[i]->name);
1550                         break;
1551                 }
1552                 ret = 1;
1553         }
1554         return ret;
1555 }